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Chemical seed treatment is a recommended technique to protect seeds from pathogens that can affect their quality. The objective of this work was to analyse the quality of soybean seeds with different treatments under different storage temperatures. Seeds of cultivar ‘M 8378 IPRO’ produced in Mato Grosso, Brazil were used. A completely randomised design was used in a 4 × 3 two-factorial scheme. The seeds were treated with three different combinations of chemicals (fungicides, insecticides, polymer and drying powder) in addition to the control (untreated seeds) combined with three different storage temperatures (13 °C, 19 °C and uncontrolled temperature), with three repetitions. Quality was assessed by the germination test (TG), accelerated aging (AA), field emergence (FE), tetrazolium test (TZ) and isoenzyme analysis. The uncontrolled storage temperature negatively influenced the variables germination, accelerated aging and field emergence. The vigour and viability of the tetrazolium test showed that untreated seeds had better physiological quality than seeds with chemical treatment. The expression of isoenzymes showed a difference between treatments. Even with the stress caused by the seed treatment, this tool is very important for the initial protection of the seedlings.

The aim of this study was to evaluate the physiological quality of soybean seeds submitted or not to dynamic cooling, and kept in cold storage (CS) and non-cold storage (NCS). A soybean seeds lot, variety M7639RR, was divided into two parts, and each one was subdivided into three parts that were subjected to one of these cooling procedure: seeds without cooling (SWC), dynamic cooling at 17 °C (SC17), and dynamic cooling at 13 °C (SC13). Seeds were kept in CS and NCS at 20 °C. Samples were collected at six times (0, 45, 90, 135, 180 and 225 days), and then submitted to germination, tetrazolium, accelerated aging and seedling emergence tests. Dynamic artificial cooling at 13 °C followed by maintenance at 20 °C ensured the preservation of physiological quality of soybean seeds for up to 225 days. The vigor of the soybean seeds subjected to dynamic cooling at 13 °C was better preserved than that of the non-cooled or of the cooled at 17 °C ones and kept in NCS for 225 days. CS at 20 °C contributed to the preservation of the physiological quality of the soybean seeds, regardless of whether or not they were submitted to the dynamic procedure. Resumo: O objetivo do trabalho foi avaliar a qualidade fisiológica de sementes de soja submetidas ou não ao resfriamento dinâmico e mantidas em armazém resfriado (AR) e não resfriado (ANR). Um lote de sementes de soja, variedade M7639RR, foi dividido em duas partes, que foram subdivididas em três partes, cada uma submetida a um procedimento de resfriamento: sementes não resfriadas (SNRE), resfriamento dinâmico a 17 °C (SRE17) e a 13 °C (SRE13). As sementes foram mantidas em um ANR e em AR a 20 °C. Foram coletadas amostras em seis momentos (0, 45, 90, 135, 180 e 225 dias), e as sementes foram submetidas aos testes de germinação, tetrazólio, envelhecimento acelerado e emergência de plântulas em canteiro. O resfriamento dinâmico artificial a 13 ºC seguido de manutenção em AR a 20 ºC assegurou a preservação da qualidade fisiológica de sementes de soja por até 225 dias. Sementes de soja submetidas ao resfriamento dinâmico a 13 °C preservam melhor o vigor, comparativamente às não resfriadas ou resfriadas a 17 °C e mantidas em ANR por 225 dias. O AR a 20 °C contribui para preservação da qualidade fisiológica da semente de soja, independentemente de a semente ser ou não submetida ao procedimento dinâmico.